Ali Babar, Fahad Muhammad, Ullah Shahid, Ahmed Hawreen, Alyousef Rayed, Deifalla Ahmed
Department of Civil Engineering, COMSATS University Islamabad-Sahiwal Campus, Sahiwal 57000, Pakistan.
Department of Civil Engineering, University of Engineering & Technology (UET), Peshawar 25000, Pakistan.
Materials (Basel). 2022 Apr 2;15(7):2616. doi: 10.3390/ma15072616.
The issue of brittleness and low post-peak load energy associated with the plain HSC led to the development of fiber-reinforced concrete (FRC) by using discrete fiber filaments in the plain matrix. Due to the high environmental impact of industrial fibers and plasticizers, FRC development is ecologically challenged. Sustainability issues demand the application of eco-friendly development of FRC. This study is aimed at the evaluation of coir as a fiber-reinforcement material in HSC, with the incorporation of silica fume as a partial replacement of cement. For this purpose, a total of 12 concrete mixes were produced by using three different doses of coir (0%, 1%, 1.5%, and 2% by wt. of binder) with silica fume (0%, 5%, and 10% as volumetric replacements of cement). The examined parameters include compressive strength, shear strength, splitting tensile strength, ultrasonic pulse velocity, water absorption, and chloride ion permeability. The scanning electron microscopy (SEM) technique was adopted to observe the microstructure of the CF-reinforced concrete. The results revealed that due to the CF addition, the compressive strength of HSC reduces notably; however, the splitting tensile strength and shear strength experienced notable improvements. At the combined incorporation of 1.5% CF with 5% silica fume, the splitting tensile strength and shear strength of the concrete experienced improvements of 47% and 70%, respectively, compared to that of the control mix. The CF incorporation is detrimental to the imperviousness of concrete. The combined incorporation of CF and silica fume is recommended to minimize the negative effects of CF on the permeability resistance of concrete. The SEM results revealed that CF underwent a minor shrinkage with the age.
普通高性能混凝土存在脆性问题以及峰值后荷载能量较低的问题，这促使人们通过在普通基体中使用离散纤维丝来开发纤维增强混凝土（FRC）。由于工业纤维和增塑剂对环境影响较大，FRC的发展面临生态挑战。可持续发展问题要求对FRC进行生态友好型开发。本研究旨在评估椰壳纤维作为高性能混凝土中的纤维增强材料，并掺入硅灰以部分替代水泥。为此，通过使用三种不同剂量的椰壳纤维（占胶凝材料重量的0%、1%、1.5%和2%）以及硅灰（分别作为水泥的体积替代物0%、5%和10%）制备了总共12种混凝土混合料。所检测的参数包括抗压强度、抗剪强度、劈裂抗拉强度、超声脉冲速度、吸水率和氯离子渗透性。采用扫描电子显微镜（SEM）技术观察椰壳纤维增强混凝土的微观结构。结果表明，由于添加了椰壳纤维，高性能混凝土的抗压强度显著降低；然而，劈裂抗拉强度和抗剪强度有显著提高。与对照混合料相比，当1.5%的椰壳纤维与5%的硅灰混合掺入时，混凝土的劈裂抗拉强度和抗剪强度分别提高了47%和70%。掺入椰壳纤维对混凝土的抗渗性不利。建议将椰壳纤维和硅灰混合掺入，以尽量减少椰壳纤维对混凝土抗渗性的负面影响。扫描电子显微镜结果表明，随着龄期的增长，椰壳纤维出现了轻微收缩。
